Smoking

Summary

• Smoking increases all-cause mortality mainly by raising the risk of cardiovascular disease, cancer, and chronic lung disease, which leads to more premature deaths.
• Across large long-term cohort studies, current smokers typically lose about 7–11 years of life compared with never-smokers.
• Risk follows a clear dose–response: more cigarettes per day and more years smoked generally means higher mortality risk.
• There is no safe level: even low-intensity or nondaily smoking increases all-cause mortality compared with never smoking.
• Quitting works at any age, and the longer you stay smoke-free, the closer your risk gets to that of never-smokers.

Factor description

This factor measures a person’s current smoking status and history of tobacco smoking. It usually captures:

• Whether you smoke now (daily or not daily)
• Whether you used to smoke but quit
• How long ago you quit (time since quitting, in years)

Most assessments use self-report. Some studies also use biomarkers (like cotinine), but KamaLama’s categories are typically based on self-reported status and time since quitting.

Impact on all-cause mortality

1. Main pathways to higher mortality

• Cardiovascular disease: smoking accelerates atherosclerosis, increases clot risk, raises inflammation, and damages blood vessels, which increases heart attack and stroke risk.
• Cancer: smoking exposes the body to carcinogens that increase the risk of multiple cancers (especially lung cancer).
• Chronic lung disease and infections: smoking damages airways and lung tissue, increasing COPD risk and vulnerability to respiratory illness.

These cause-specific deaths add up to higher all-cause mortality because they are common, serious, and often occur earlier in life.

2. Dose–response pattern (more exposure, more risk)

• Studies consistently show a graded relationship: higher intensity (cigarettes per day) and longer duration (years smoked) are linked to higher all-cause mortality.
• No clear safe threshold has been identified. Even nondaily or low-intensity smoking shows elevated risk versus never smoking.

3. Cessation effect (risk falls after quitting)

• After quitting, mortality risk declines over time. The size and speed of recovery vary by prior intensity and duration, and by how long ago quitting occurred.
• Earlier cessation generally restores more lost years, but quitting later still provides meaningful benefit compared with continuing to smoke.

Patterns

• Age: the cumulative harm increases with longer exposure over the life course, so long-term smokers tend to have higher risk.
• Socioeconomic disparities: smoking is often more common in disadvantaged groups in many countries, contributing to avoidable gaps in life expectancy.
• Health comorbidity: people with chronic conditions (for example, cardiovascular disease or chronic lung disease) often experience larger absolute benefits from quitting because baseline risk is higher.
• Mental health and substance-use burden: some populations with higher smoking prevalence can experience especially large mortality impacts at the population level.

KamaLama scoring

KamaLama treats smoking as a high-impact risk factor with a strong time-since-quitting recovery pattern. The scoring is a hybrid approach:

• Current smoking gets a large negative score because risk is actively elevated.
• Nondaily smoking still receives a meaningful penalty because there is no proven safe level.
• Former smoking improves stepwise as time since quitting increases, reflecting risk reduction over time.
• Long-term abstinence (10+ years) is scored similar to never smoking in this simplified model.

Practical tips

• Start with one simple step: remove cigarettes/vapes/lighters/ashtrays from your main spaces (home, car, bag) to reduce cues.
• Pick a quit date within the next 2–4 weeks and write it down (calendar reminder + tell one supportive person).
• Identify your top 2–3 triggers (coffee, stress, alcohol, after meals) and choose a replacement action for each (gum, short walk, deep breathing, texting someone).
• Make your environment help you: avoid “high-trigger” situations for the first 1–2 weeks if possible, or go with a supportive friend who knows you are quitting.
• Use proven supports if needed: quitlines, counseling, and approved nicotine replacement or prescription options can increase success (especially for daily smokers).
• Track progress in time since quitting (weeks → months → years). In KamaLama, your score improves as your smoke-free time increases.
• If you slip, treat it as a data point, not failure: return to your plan the same day and adjust the trigger that caused it.

References

• Authoritative guidelines / evaluations

  • World Health Organization (WHO) (2023). Tobacco. https://www.who.int/news-room/fact-sheets/detail/tobacco
  • U.S. Centers for Disease Control and Prevention (CDC) (2024). Health Effects of Cigarette Smoking. https://www.cdc.gov/tobacco/about/cigarettes-and-health/index.html

• Peer-reviewed / indexed research

  • Doll R, Peto R, Boreham J, Sutherland I (2004). Mortality in relation to smoking: 50 years' observations on male British doctors. https://doi.org/10.1136/bmj.38142.554479.AE
  • Banks E, Joshy G, Weber M, et al. (2015). Tobacco smoking and all-cause mortality in a large Australian cohort study. https://doi.org/10.1186/s12916-015-0281-z
  • Inoue-Choi M, Liao LM, Reyes-Guzman C, et al. (2017). Long-term, low-intensity smoking and mortality (NIH-AARP). https://doi.org/10.1001/jamainternmed.2016.7511
  • Inoue-Choi M, Christensen CH, Rostron BL, et al. (2020). Dose-response of low-intensity and nondaily smoking with mortality. https://doi.org/10.1001/jamanetworkopen.2020.6436
  • Taylor DH, Hasselblad V, Henley SJ, Thun MJ, Sloan FA (2002). Benefits of smoking cessation for longevity. https://doi.org/10.2105/ajph.92.6.990